This invention relates generally to a method of generating graphics such as the drawings and the data thereon needed for construction of an industrial plant or like project. More specifically, it is involved with the utilization of a general purpose computer employing optically scanned information taken from a design model in the generation of isometric engineering drawings as are needed for piping fabrication and installation in the construction of an industrial plant.
The fabrication and eventual installation of piping systems utilized in processing plants or similar projects involve a very substantial design effort and constitute a major part of the plant cost. Making isometric engineering drawings for such piping systems can not only be difficult but usually requires a great deal of skilled effort. In large oil refineries or chemical plants the design effort for the piping system alone can involve a matter of one third of the total design effort necessary to complete the final plant construction. Frequently, the piping system for such projects will be the last to be completed since the design of large fluid handling vessels must be finalized before locations for the piping and associated equipment can be precisely determined.
Large scale industrial processing plants require substantial quantities of piping, valves, fittings and associated components. These items are required in many different sizes, pressure ratings, materials of construction, end connections and other special features since for each class of service the correct selection of associated piping equipment must be made. For example, in a processing plant piping system, the handling of fluids at high pressure, the handling of high corrosive fluids at different pressures and temperatures plus handling steam, water etc. all add to the complexities required to be considered in design, fabrication and final installation in the completed industrial plant.
Pipe line systems for the industrial plant must be carefully dimensioned on isometric engineering drawings so that after fabrication in a welding shop, possibly remote from the plant location, they can be assembled in the field at the plant location and meet rigid and strict space tolerances. Obviously, to bend or stretch a section of large diameter welded pipe after fabrication to fit it into place is not a realistic possibility.
The isometric engineering drawings needed for piping fabrication and installation in the construction of an industrial plant should advantageously also identify the sizes, quantity, specifications, characteristics, etc. of hundreds of different piping items. These items must be ordered early in the design period to ensure that they will be available at the job site when needed. Frequently, erection of the piping system is a controlling factor in the construction schedule. Hence, missing materials or items can adversely affect the completion date for the entire plant project.
The graphics, such as isometric engineering drawings, needed for construction of an industrial plant have been produced under the teachings of the prior art with the aid of general purpose computing apparatus supplying electronic signals to a graphics plotter to produce the graphics. The input to such a general computer facilitates the computer selecting and dimensionally calculating, to correct scale, associated piping and equipment by utilization of only a minimum input of coded data presented to the computer. For example, Rosenthal et al U.S. Pat. No. 4,181,954 of Jan. 1, 1980 discloses a prior art computer aided graphics system.
Under the teachings of this Rosenthal et al patent an originator/designer must study all available two dimensional layouts, drawings and three dimensional models of the pipeline to be described. He then must mentally translate what he studies to manually encode the data that he has assembled onto a data sheet in a predetermined selected format. Then additional personnel are required, in the form of keypunch operators, who must keypunch the data from this data sheet into a binary code format on a deck of punched cards. This card deck is then combined with a computer program deck of cards, this latter deck being read into the computer in accordance with commands from a central control.
Through operation of the general purpose computer under the teachings of the Rosenthal et al patent, control signals are generated for manipulating the input data coming from the card deck manually produced by the keypunch operators. The general purpose computer then records its output onto a magnetic tape which supplies electronic plotting signals to a cathode ray tube plotter. This type of plotter converts the plotting tape signals into lines and letters, and records the information into microfilm at high speed. Visual enlargement from this microfilm product is carried out to complete isometric engineering drawings on paper vellum. These enlargements will portray the actual isometric drawings with a list of materials, notes, references, titles and other data on one portion of these drawings.
Although the procedures suggested in the above mentioned Rosenthal et al patent are advantageous in the generation of graphics such as isometric engineering drawings needed for piping fabrication and installation in the construction of an industrial plant project, they do necessitate the originator/designer to analyze and mentally transpose onto a coded data sheet the layouts, studies, models, etc., as the input information which he has to code onto the sheet. Then further personnel are required to take this multiplicity of data sheets and operate keypunch machines to punch the data from the sheets onto computer punch cards which, as a complete deck, reflect the data from the multitude of sheets produced by the originator/designer. Then this deck of hundreds of loose cards is supplied to a general purpose computer for integration with a compatible computer system program whereupon electronic plotting signals are supplied to a graphics plotter to produce the graphics to be used in construction of the full size industrial plant.